Help your preschoolers collect objects to be used in a creative building enterprise. Gather objects like empty boxes, canisters and building blocks and place them on a flat surface. Use vocabulary words to prompt preschoolers to build a castle, school or other building. Have students take turns as you instruct them to place the blue block under the red one, on top of the green one, inside the house or in the middle of two other blocks. You can also observe the kids' self-directed play and introduce the vocabulary as you go.
Practice writing, reading and spatial relations as your preschoolers create labels for objects in your classroom. Place a card reading "under" under a table or "far" at the very back of the classroom, furthest from the kids' desks. Let preschoolers decide where the labels should go, only correcting students as necessary so that they can demonstrate the meanings of the words for themselves and each other.
Have students pair up to act out spatial relations vocabulary. Whisper a word to each student and have them take turns acting out their word for their partner. A preschooler who as the word "far" may run all the way across the classroom, while a student who has the word "inside" might crawl inside a box or playhouse. You can demonstrate the words to introduce the idea of spatial relations if your preschoolers are not ready to work in pairs.
Create some spatial relations fun with music a few simple dance moves. Place the preschoolers in pairs, then have them place their hands and arms in various over/under positions with each other. After preschoolers have chosen a few of their favorite moves, turn on the music and ask them to demonstrate their moves as a dance routine for the rest of the class. They can verbally identify which parts are over and which are under as they dance.